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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 235 records · Page 13
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Land surface temperature measurements for EOS MODIS data

Work accomplished includes: Beta delivery 1 of the MODIS LST product; the first version of MODIS LST ATBD; update of the atmospheric radiative transfer code ATRAD; the development of a new approach look-up table method; and improvement of the TIR spectrometer. Preliminary feasibility analysis of the look-up table approach is presented in terms of showing the effects on the TIR radiance at the top of the atmosphere of the stratospheric and upper atmospheric temperature profiles, the surface emissivity and temperature, the lower atmospheric temperature and water vapor profiles, and the viewing angle.

Wan, Zhengming↗
NASA NTRS2018

Intraseasonal Variations of Nonmigrating Tides Observed Near the Mesopause

Nonmigrating tides excited in the tropical troposphere by latent heat release from deep convection are known to be responsible for introducing the longitudinal structures in the upper atmosphere and the ionosphere. This study presents for the first time an extensive analysis of the prominent wave-3 and wave-4 longitudinal structures using nearly 14 years of temperature observations by the Microwave Limb Sounder instrument operated on the Aura satellite from 2004 to 2017. The observations reveal significant intraseasonal (~30-60 days) periodic variations in the amplitudes of these wave structures at ~97-km altitude near the mesopause. Some large wave amplitudes accompany strong activity of the Madden-Julian Oscillation. Rainfall data from the Tropical Rainfall Measuring Mission are used as a proxy of latent heating to investigate the source of these variations. Intraseasonal signatures in the wave structures are observed to coincide with the rainfall variations, indicating that the tropospheric 30- to 60- day oscillation is an important driver of the same periodic changes in the upper atmosphere. Given that not all intraseasonal oscillations in the lower atmosphere have corresponding signatures in the longitudinal wave structures, the atmospheric conditions and other influences are important. This study provides evidence on the connection between intraseasonal variations of tides in the upper atmosphere and the changes in the forcing by latent heat release in the troposphere.

Liu, Guiping↗
NASA NTRS1980

High-resolution Martian atmosphere modeling

A multilayer radiative transfer, high-spectral-resolution infrared model of the lower atmosphere of Mars has been constructed to assess the effect of scattering on line profiles. The model takes into accout aerosol scattering and absorption and includes a line-by-line treatment of scattering and absorption by CO2 and H2O. The aerosol complex indices of refraction used were those measured on montmorillonite and basalt chosen on the basis of Mars ir data from the NASA Lear Airborne Observatory. The particle sizes and distribution were estimated using Viking data. The molecular line treatment employs the AFGL line parameters and Voigt profiles. The modeling results indicate that the line profiles are only slightly affected by normal aerosol scattering and absorption, but the effect could be appreciable for heavy loading. The technique described permits a quantitative approach to assessing and correcting for the effect of aerosols on lineshapes in planetary atmospheres.

Egan, W. G.↗
NASA NTRS1984

Atmospheric science experiments applicable to Space Shuttle Spacelab missions

The present lack of a lower atmosphere research satellite program for the 1980s has prompted consideration of the Space Shuttle/Spacelab system as a means of flying sensor complements geared toward specific research problems, as well as continued instrument development. Three specific examples of possible science questions related to precipitation are discussed: (1) spatial structure of mesoscale cloud and precipitation systems, (2) lightning and storm development, and (3) cyclone intensification over oceanic regions. Examples of space sensors availab le to provide measurements needed in addressing these questions are also presented. Distinctive aspects of low-earth orbit experiments would be high resolution, multispectral sensing of atmospheric phenomena by complements of instruments, and more efficient sensor development through reflights of specific hardware packages.

Wilson, G. S.↗
NASA NTRS1998

Radio Occultation Studies of Venus' Atmosphere with Magellan

We have been conducting a systematic study of the middle and lower atmosphere of Venus through analysis of 20 radio occultation experiments conducted with the Magellan spacecraft between October, 1991, and August, 1994. These studies have revealed a rich but sparsely sampled trove of information regarding the structure, composition and dynamics of the Venus atmosphere. The five sets of experiments sampled a variety of latitudes. Basic results include vertical profiles of: (1) electron density in the ionosphere, (2) pressure, temperature, density, and static stability in the neutral atmosphere (from 33 km to 98 km), and (3) sulfuric acid vapor (H2SO4) abundance below the main cloud deck. Further analysis of the temperature profiles led to the discovery of small vertical-scale gravity waves in the neutral atmosphere. The retrieved profiles show intriguing zonal variations that might be due to planetary- scale waves. During the performance period of this grant, we have concentrated on reanalyzing the 15 experiments conducted in 1994 using improved trajectory files for Magellan provided by JPL, obtaining more reliable results, and on conducting an error analysis of the derived profiles. In addition, we have begun an analysis of microwave emission maps of Venus obtained at the Very Large Array (VLA) in April, 1996. This report is organized as follows: A summary of results is presented, giving representative examples of the various physical profiles retrieved from all the Magellan radio occultation studies, emphasizing latitudinal variations evident in the data. Next, a preliminary analysis of the VLA maps is given. A summary of activities follows the scientific results, detailing papers published and presented at various conferences. This report concludes with a "Conclusions and Suggestions for Future Work" section.

Jenkins, Jon M.↗
NASA NTRS1974

The aurora as a source of planetary-scale waves in the middle atmosphere

Photographs of global scale auroral forms taken by scanning radiometers onboard weather satellites in 1972 show that auroral bands exhibit well organized wave motion with typical zonal wave number of 5 or so. The scale size of these waves is in agreement with that of well organized neutral wind fields in the 150- to 200-km region during the geomagnetic storm of May 27, 1967. Further, the horizontal scale size revealed by these observations are in agreement with that of high altitude traveling ionospheric disturbances. It is conjectured that the geomagnetic storm is a source of planetary and synoptic scale neutral atmospheric waves in the middle atmosphere. Although there is, at present, no observation of substorm related waves of this scale size at mesospheric and stratospheric altitudes, the possible existence of a new source of waves of the proper scale size to trigger instabilities in middle atmospheric circulation systems may be significant in the study of lower atmospheric response to geomagnetic activity.

Chiu, Y. T.↗
NASA NTRS1975

The aurora as a source of planetary-scale waves in the middle atmosphere

Photographs of global-scale auroral forms taken by scanning radiometers onboard U.S. Air Force weather satellites in 1972 show that auroral bands exhibit well-organized wave motion with typical zonal wave number of 5 or so. The scale size of these waves is in agreement with that of well-organized neutral wind fields measured by the 1967-50B satellite in the 150- to 220-km region during the geomagnetic storm of May 27, 1967. The horizontal scale size revealed by these observations is in agreement with that of high-altitude traveling ionospheric disturbances. It is conjectured that the geomagnetic storm is a source of planetary and synoptic scale neutral atmospheric waves in the middle atmosphere. The possible existence of a source of waves of the proper scale size to trigger instabilities in middle atmospheric circulation systems may be significant in the study of lower atmospheric response to geomagnetic activity.

Chiu, Y. T.↗
NASA NTRS2008

Titan Flagship Mission 3-Degree-of-Freedom Simulation Analysis

A NASA flagship mission to Titan, the largest moon of Saturn and the only moon in the solar system with a significant atmosphere, has been designed that uses three separate spacecraft, each requiring significant interaction with the atmosphere. The first vehicle is a Titan lander for lower-atmosphere and surface science. The second is an aerial vehicle for aerial science at approximately 10 km altitude with an expected lifetime of one year. This spacecraft will use the natural winds of Titan to cover a large area over its lifetime. The third vehicle is a Titan orbiter that will interact with the atmosphere in two respects. The first atmospheric interaction is the orbital insertion maneuver that will be accomplished using aerocapture, during which time the hyperbolic approach of 6.5 km/s will be reduced to 1.6 km/s over 41 minutes with an exit periapsis altitude of 130 km. The second atmospheric interaction occurs after a propulsive maneuver has raised the periapsis after aerocapture to 1170 km, where the atmosphere will be sampled over several months. This is the first phase of aerosampling that covers southern latitudes. After a 3.3-year circular science phase at an altitude of 1700 km, a second phase of additional aerosampling is performed sampling northern latitudes. The atmospheric trajectory analysis for these three spacecraft will be discussed throughout this paper.

Prince, Jill L.↗
NASA NTRS1994

Special relativity effects for space-based coherent lidar experiments

There is a great need to develop a system that can measure accurately atmospheric wind profiles because an accurate data of wind profiles in the atmosphere constitutes single most input for reliable simulations of global climate numerical methods. Also such data helps us understand atmospheric circulation and climate dynamics better. Because of this need for accurate wind measurements, a space-based Laser Atmospheric Winds Sounder (LAWS) is being designed at MSFC to measure wind profiles in the lower atmosphere of the earth with an accuracy of 1 m/s at lower altitudes to 5m/s at higher altitudes. This system uses an orbiting spacecraft with a pulsed laser source and measures the Doppler shift between the transmitted and received frequencies to estimate the atmospheric wind velocities. If a significant return from the ground (sea) is possible, the spacecraft speed and height are estimated from it and these results and the Doppler shift are then used to estimate the wind velocities in the atmosphere. It is expected that at the proposed wavelengths, there will be enough backscatter from the aerosols but there may no be significant return from the ground. So a coherent (heterodyne) detection system is being proposed for signal processing because it can provide high signal to noise ratio and sensitivity and thus make the best use of low ground return. However, for a heterodyne detection scheme to provide the best results, it is important that the receiving aperture be aligned properly for the proposed wind sounder, this amounts to only a few microradians tolerance in alignment. It is suspected that the satellite motion relative to the ground may introduce errors in the order of a few microradians because of special relativity. Hence, the problem of laser scattering off a moving fixed target when the source and receiver are moving, which was not treated in the past in the literature, was analyzed in the following, using relativistic electrodynamics and applied to the case of the space-based coherent lidar, assuming flat ground. Here an interest in developing analytical expression for the location of the receiving point for the return with respect to the satellite, receiving angle and Doppler shift in frequency and amount of tip, all as measured in the satellite moving coordinate system and the diffuse scattering angle at the ground which does not require any compensation. All the three cases of retro-reflection, specular reflection and diffuse scattering by the ground should be treated though retro-reflection and diffuse scattering are more important.

Raogudimetla, V. S.↗
DOE OSTI2025

Observations of surface energy fluxes and meteorology in the seasonally snow-covered high-elevation East River watershed during SPLASH, 2021–2023

Abstract. From autumn 2021 through summer 2023, scientists from the National Oceanic and Atmospheric Administration (NOAA) and partners conducted the Study of Precipitation, the Lower Atmosphere, and Surface for Hydrometeorology (SPLASH) campaign in the East River watershed of Colorado. One objective of SPLASH was to observe the transfer of energy between the atmosphere and the surface, which was done at several locations. Two remote sites were chosen that did not have access to power utilities. These were along the valley floor near the East River in the vicinity of the unincorporated town of Gothic, Colorado. Energy balance measurements were made at these locations using autonomous, single-level flux towers referred to as atmospheric surface flux stations (ASFSs). The ASFSs were deployed on 28 September 2021 at the Kettle Ponds Annex site and on 12 October 2021 at the Avery Picnic site and operated until 19 July and 21 June 2023, respectively. Measurements included basic meteorology; upward and downward longwave and shortwave radiative fluxes and subsurface conductive flux, each at 1 min resolution; 3-D winds from a sonic anemometer and H2O/CO2 from an open-path gas analyzer, both at 20 Hz from which sensible, latent heat, and CO2 fluxes were derived; and profiles of soil properties in the upper 0.5 m (both sites) and temperature profiles through the snow (at Avery Picnic), each reported between 10 min and 6 h. The system uptime was 97 % (Kettle Ponds) and 90 % (Avery Picnic), and collectively 1184 d of data was obtained between the stations. The purpose of this article is to document the ASFS deployment at SPLASH, to document the data acquisition and post-processing of measurements, and to serve as a guide for interested users of the data sets, which are archived at Zenodo (https://doi.org/10.5281/zenodo.10313363, Cox et al., 2023b; https://doi.org/10.5281/zenodo.10327409, Cox et al., 2023c; https://doi.org/10.5281/zenodo.10313894, Cox et al., 2023d; https://doi.org/10.5281/zenodo.10307825, Cox et al., 2023e; https://doi.org/10.5281/zenodo.10310520, Cox et al., 2023f) with the Creative Commons Attribution 4.0 International license.

Cox, Christopher J. (ORCID:0000000322037173)↗
NASA NTRS1985

Sensitivity of depth of maximum and absorption depth of EAS to hadron production mechanism

Comparison of experimental data on depth of extensive air showers (EAS) development maximum in the atmosphere, T sub M and path of absorption, lambda, in the lower atmosphere of EAS with fixed particle number in the energy region eV with the results of calculation show that these parameters are sensitive mainly to the inelastic interaction cross section and scaling violation in the fragmentation and pionization region. The data are explained in a unified manner within the framework of a model in which scaling is violated slightly in the fragmentation region and strongly in the pionization region at primary cosmic rays composition close to the normal one and a permanent increase of inelastic interaction cross section. It is shown that, while interpreting the experimental data, disregard of two methodical points causes a systematic shift in T sub M: (1) shower selection system; and (2) EAS electron lateral distribution when performing the calculations on basis of which the transfer is made from the Cerenkov pulse FWHM to the depth of shower maximum, T sub M.

Antonov, R. A.↗
NASA NTRS1988

Carbon dioxide in the atmosphere over the Amazon Basin

As a part of the NASA's Amazon Boundary Layer Experiment 2A mission, the cycle of atmospheric CO2 over the Amazon Basin was examined using measured vertical profiles of CO2 concentrations in the canopy and aloft, and direct measurements of CO2 emissions from soils. The results provide a detailed picture of daily exchanges of air between the tropical forest (0-30) and the atmospheric boundary layer (30-2000 m). A comparison of atmospheric CO2 distributions over forests, wetlands, and rivers shows that the lower atmosphere over forests functions separately from that over rivers or wetlands during the night and to some extent during the day; the basic diurnal cycle of CO2 over wetlands is much weaker than over forests, and the cycle is almost absent over rivers. This result is consistent with expectations based on the biogeochemistry of organic carbon in these systems.

Wofsy, Steven C.↗
NASA NTRS1991

Upper Atmosphere Research Satellite (UARS): A program to study global ozone change

A general overview of NASA's Upper Atmosphere Research Satellite (UARS) program is presented in a broad based informational publication. The UARS will be responsible for carrying out the first systematic, comprehensive study of the stratosphere and will furnish important new data on the mesosphere and thermosphere. The UARS mission objectives are to provide an increased understanding of energy input into the upper atmosphere; global photochemistry of the upper atmosphere; dynamics of the upper atmosphere; coupling among these processes; and coupling between the upper and lower atmosphere. These mission objectives are briefly described along with the UARS on-board instrumentation and related data management systems.

Source record↗
NASA NTRS1994

Comet Shoemaker-Levy-9 impact with Jupiter: Aeronomical predictions

The fragments of comet Shoemaker-Levy-9 will enter the atmosphere of Jupiter during July 20-26, 1994. Significant amounts of water vapor will be injected into the upper atmosphere of Jupiter either from the comet itself or from the lower atmosphere of Jupiter. The photochemistry of both the neutral gas and the ionosphere will be greatly altered by the influx of this water vapor or the atomic oxygen generated by the dissociation of the water. Enhanced abundances of H2O (or other species such as NH3) in the atmosphere above the homopause should persist for at least a year and should be globally distributed. The odd oxygen (i.e., O or H2O or OH) associated with the cometary water influx alters the ion chemistry by removing H(+) ions, which also has the effect of reducing the ionospheric electron density because H(+) is ordinarily the main ion species in the Jovian ionosphere. The density of H3(+), both in the auroral and non-auroral ionosphere, will also be reduced due to presence of water. This ion species has been detected spectroscopically at Jupiter, and a drop in its abundance should be detectable. The major ion species will become H3O(+) which could reach a peak density as high as 10(exp 4)/cu cm in the non-auroral ionosphere and 10(exp 5)/cu cm in the auroral ionosphere. It should be possible to detect this ion species spectroscopically from Earth-based observatories.

Cravens, T. E.↗
NASA NTRS1978

Martian atmosphere modeling between 0.4 and 3.5 microns - Comparison of theory and experiment

A model of the lower atmosphere of Mars has been constructed that combines aerosol absorption and scattering with a line-by-line analysis of CO2 and H2O in a multilayer radiative transfer program. Aerosol composition previously inferred from the NASA Lear Jet Observatory data was used to measure the optical complex indices of refraction of appropriate Martian analogs from 0.4 to 2.5 microns. The aerosol vertical particle density scale was deduced using the Viking camera observations of the soil and sky intensities between 0.4 and 1.0 microns in comparison with those modeled using a multilayer Mie scattering program. A comparison of observed Mars atmospheric absorptions was made with those obtained using Lorentz, Voigt, and Doppler line profiles in a multilayer model of the CO2 and H2O. The Voigt line profile of CO2 absorption at approximately 4976 kaysers was then combined in a multilayer aerosol model of the Martian atmosphere. An evaluation of the effect on the line shape was made using several aerosol loadings.

Egan, W. G.↗
NASA NTRS1973

Error analysis for the Mariner-6 and -7 occultation experiments.

The Mariner-6 and -7 occultation experiments provide sets of Doppler residuals from which physical properties of the Martian atmosphere, such as the ionospheric electron-density distribution and the lower-atmosphere temperature profile, may be derived. The Doppler residuals contain both systematic and random errors. The former are removed during the data reduction, and the latter are analyzed to yield error limits on the derived physical properties of the atmosphere.

Stewart, R. W.↗
NASA NTRS1989

Wave propagation into the middle atmosphere

Recent observations of various types of waves propagating into the middle atmosphere are reviewed. Emphasis is made on the excitation processes in the lower atmosphere and their vertical propagation through the background flow as a function of the latitude, height and season. The following subjects are discussed: (1) Vertical propagation of quasi-stationary forced Rossby waves into the winter stratosphere in connection with the sudden warming; (2) Spectral distribution and seasonal characteristics of normal mode (free) Rossby waves and the asymmetry of the Northern and Southern Hemispheres; and (3) Seasonal variation of internal gravity waves in the middle atmosphere. Further discussions are presented for future studies based on accumulated observational data during the MAP period.

Hirota, I.↗